The other answers are better, but here's a
unixy "no modules" solution just for the heck of it:
# Usage: $teed_fh = tee @output_handles;
# Returns a new filehandle that, when written, copies to all @output_h
+andles
sub tee {
use vars qw(*__TEE_FH);
my $tfh = do { \local *__TEE_FH }; # XXX Should use IO::Handle ins
+tead
defined( my $pid = open($tfh, "|-") ) or die "fork: $!";
return select((select($tfh), $| = 1)[0]) if $pid;
for (@_) { select($_); $| = 1 }
while( sysread(STDIN, my $block, 8192) ) { print $_ $block for @_
+}
kill 9,$$ or exit; # XXX Should use POSIX::_exit instead
}
and an example using it to do what you wanted:
# Tee STDOUT to a log file
use vars qw(*LOG);
open LOG, ">>log.txt" or die "log.txt: $!";
*STDOUT = tee(*STDOUT, *LOG);
END { close STDOUT and wait }
# Now do something that writes to STDOUT
print "Hello, world #$_!\n" for (1..20);
# XXX But, should have just used IO::Tee in first place :)
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